Mobile based lexicon and forecasting

ABSTRACT

An approach is provided for ranking candidate answers to a natural language question. A natural language question is received from a user of a mobile device. Candidate answers to the received natural language question are generated. A lexicon is generated based on contextual information of the user determined by the mobile device. Contextual information of the user is forecasted based on usage of the mobile device. Based in part on the lexicon and the forecasted contextual information, the candidate answers to the natural language question are ranked.

TECHNICAL FIELD

The present invention relates to information retrieval and naturallanguage processing, and more particularly to managing candidate answersin a natural language query and answer system.

BACKGROUND

Natural language processing (NLP) systems are attempting to minimizeuncertainty from reasoning through the use of known lexicons,ontologies, and corpora ingestion, but overall system accuracy usingthese known techniques has limitations. A known probabilisticdistributed NLP system delivers answers to questions by parsing anatural language query in input text provided by a user, searching formultiple candidate answers to the query in its data set, and assigningconfidence scores to the candidate answers. The probabilisticdistributed NLP system can, in a limited way, take into account thecontext of the user who provided the input text if the context isappended to the query. Appending such context to a query, however, doesnot provide an ideal user experience because the combination of thequery and the appended portion is not in the form of a question thatwould be posed naturally by a user. A known web search engine beingutilized via a user's mobile device can take into account contextconsisting of the user's geographic location by processing search termsbased in part on the user's location, which is provided by a globalpositioning system (GPS) incorporated into the device.

BRIEF SUMMARY

In first embodiments, the present invention provides a method of rankingcandidate answers to a natural language question. The method includes acomputer receiving the natural language question from a user of a mobiledevice. The method further includes the computer generating candidateanswers to the received natural language question. The method furtherincludes the computer generating a lexicon based on contextualinformation of the user determined by the mobile device. The methodfurther includes the computer forecasting contextual information of theuser based on usage of the mobile device. The method further includes,based in part on the lexicon and the forecasted contextual information,the computer ranking the candidate answers to the natural languagequestion.

Embodiments of the present invention enhances the accuracy of NLPquestion answering systems by allowing the knowledge base of thequestion answering system to include contextual information about auser, where the contextual information is captured by a mobile device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a system for ranking candidate answers to anatural language question, in accordance with embodiments of the presentinvention.

FIG. 2 is a flowchart of a process of ranking candidate answers to anatural language question, where the process is implemented in thesystem of FIG. 1, in accordance with embodiments of the presentinvention.

FIG. 3 depicts an example of ranking a candidate answer by stepsincluded in the process of FIG. 2, in accordance with embodiments of thepresent invention.

FIGS. 4A-4C depict forecasting algorithms that are used in the processof FIG. 2, in accordance with embodiments of the present invention.

FIG. 5 is a block diagram of a computer that is included in the systemof FIG. 1 and that implements the process of FIG. 2, in accordance withembodiments of the present invention.

DETAILED DESCRIPTION

Overview

Embodiments of the present invention provide a ranking of candidateanswers generated by a NLP question answering system in response toreceiving a natural language question from a user utilizing a mobiledevice. The ranking of the candidate answers is based on a mobile-basedlexicon and forecasted contextual information about the user. Entries inthe mobile-based lexicon are based on contextual information of theuser, as determined by the mobile device. The forecasted contextualinformation is a forecast of future behavior or interest(s) of the userbased on current and/or historical usage of the mobile device.

A known NLP question answering system provides an answer to a naturallanguage question by using traditional lexicons, ontologies and corporaingestion, but the overall system accuracy in terms of precision andrecall can be improved, which presents a unique challenge to users ofNLP systems who desire minimized uncertainty about the answer providedby the NLP system. Furthermore, a user's mobile device interacting withthe NLP question answering system presents a large number of candidateanswers, which is a unique challenge to the user's experience with themobile device based on the device having limited display space and theuser having limited time to sift through the large number of candidateanswers. At least one of these unique challenges is overcome by one ormore embodiments of the present invention.

System for Ranking Candidate Answers to a Natural Language Question

FIG. 1 is a block diagram of a system 100 for ranking candidate answersto a natural language question, in accordance with embodiments of thepresent invention. System 100 includes a computer 102, which runs asoftware-based natural language processing (NLP) question answering (QA)system 104. NLP QA system 104 receives a natural language question 106or other unstructured textual input (not shown) which is entered into amobile device 108 by a user of the mobile device 108. Natural languagequestion 106 is text in a natural language that includes a question. Asused herein, mobile device 108 is a handheld computing device such as asmartphone or a wearable computer, such as smartglasses. In response toreceiving a user entry of natural language question 106, mobile device108 sends natural language question 106 to computer 102 for processingby NLP QA system 104 via a computer network (not shown). Mobile device108 can use a combination of on-board and off-board mobile processing.

NLP QA system 104 includes the following software modules: amobile-based lexicon generator 110 and a mobile-based forecaster 112.Mobile-based lexicon generator 110 generates a lexical analyzer (notshown) and a mobile-based lexicon 114. The lexical analyzer (also knownas (a.k.a.) lexer or tokenizer) generated by mobile-based lexicongenerator 110 is a computer program that transforms a stream ofcharacters into a stream of “atomic chunks of meaning,” which are tokens(i.e., meaningful character strings). Mobile-based lexicon generator 110generates the lexical analyzer based on contextual information about theuser of mobile device 108. The generated lexical analyzer transforms astream of characters based in part on meanings of character strings,where the meanings are based on the contextual information about theuser. The mobile-based lexicon 114 is a repository of words and otherterms along with their definitions, which are ranked or otherwiseprioritized based on contextual information about the user. Theprioritization of the words and other terms in mobile-based lexicon 114can be based on historical usage of mobile device 108, geographiclocations of mobile device 108 provided by a GPS system coupled to themobile device, or other data about movement of the user or surroundingsof the user, as detected by sensor(s) coupled to mobile device 108. Thehistorical usage of mobile device 108 can include website(s) visited bythe user of mobile device 108 and search terms entered by the user intoa search engine accessed by mobile device 108.

Mobile-based forecaster 112 employs forecasting algorithm(s) to generateone or more predictions about what the contextual information of theuser of mobile device 108 will be in a specified time in the future. Thecontextual information includes interests of the user. The prediction(s)generated by mobile-based forecaster 112 can be based on historicalusage of mobile device 108, including website(s) visited by the user ofmobile device 108, search term(s) entered by the user into a searchengine, and geographic position(s) at which mobile device 108 waslocated as determined by a GPS system coupled to the mobile device.

NLP QA system 104 generates candidate answers to natural languagequestion 106. Based on the contextual information prediction(s)generated by mobile-based forecaster 112 and the prioritization ofdefinitions in mobile-based lexicon 114, NLP QA system 104 generates aranking 116 of the candidate answers.

Although not shown in FIG. 1, other embodiments include multiple mobiledevices 108 that work together to determine and provide the contextualinformation about the user, where the multiple mobile devices 108 canuse a combination of on-board and off-board mobile processing.

As one example, NLP QA system 104 is an enhancement of the Watson®question answering computing system offered by International BusinessMachines Corporation located in Armonk, N.Y., whereby the enhancementreceives the aforementioned contextual information about a user ofmobile device 108, incorporates the contextual information into a baseof knowledge, and uses the contextual information in the base ofknowledge as at least a partial basis for ranking candidate answers to anatural language question. The Watson® question answering systemdelivers answers to questions by receiving and parsing input text,looking for multiple candidate answers in its data set, and assigning aconfidence score to each of the candidate answers. In its current form,without the enhancement described herein, the Watson® question answeringsystem does not take into account the context of the user asking thequestion. For example, a user entering “What is the best way to treat mycondition of X”, where X is a medical condition, will receive the sameanswer from the known Watson® question answering system if the user islocated in Country A, Country B, Country C, or Country D when enteringthe question. The actual answer or best answer, however, may differbased in part on whether the user is currently located in Country A,Country B, Country C, or Country D (i.e., based in part on the contextof the user, where the context is the geographic location of the user).In this example, the enhancement provided by the NLP QA system 104generates a ranking of candidate answers that is based in part onwhether the user is currently located in Country A, Country B, CountryC, or Country D, where the country in which the user is located isdetermined from geographic coordinates provided by a GPS (not shown)coupled to mobile device 108.

The functionality of the components shown in FIG. 1 is described in moredetail in the discussion of FIG. 2 and FIG. 5 presented below.

Process for Ranking Candidate Answers to a Natural Language Question

FIG. 2 is a flowchart of a process of ranking candidate answers to anatural language question, where the process is implemented in thesystem of FIG. 1, in accordance with embodiments of the presentinvention. The process of FIG. 2 begins at step 200. In step 202, NLP QAsystem 104 (see FIG. 1) receives natural language question 106 (seeFIG. 1) as unstructured text from a user of mobile device 108 (see FIG.1).

In step 204, NLP QA system 104 (see FIG. 1) analyzes natural languagequestion 106 (see FIG. 1), generates candidate answers in response tonatural language question 106 (see FIG. 1), gathers evidence in supportof the candidate answers, and generates initial scores for the candidateanswers based on the gathered evidence. To analyze natural languagequestion 106 (see FIG. 1), NLP QA system 104 (see FIG. 1) generates alexical analyzer, which transforms streams of characters in naturallanguage question 106 into meaningful character strings. In step 204 andsubsequent steps of FIG. 2, NLP QA system 104 (see FIG. 1) dynamicallyadjusts the criteria for determining which character string ismeaningful or not based in part on contextual information about the user(see the discussion below relative to step 206) and based in part onforecasted contextual information about the user (see the discussionbelow relative to step 208).

In one embodiment, the candidate answers generated in step 204 arepotentially correct answers that are replies or responses to naturallanguage question 106 (see FIG. 1). In another embodiment, the candidateanswers generated in step 204 are questions that are presented to theuser of mobile device 108 (see FIG. 1) to obtain additional contextualinformation about the user or other additional information (e.g., toassist in a medical diagnosis).

Prior to step 206, NLP QA system 104 (see FIG. 1) identifies contextualinformation about the user of mobile device 108 (see FIG. 1), where thecontextual information has been determined by mobile device 108 (seeFIG. 1). The aforementioned contextual information about the user caninclude interest(s) of the user and is determined by any combination of:(1) a list of applications that the user has run on mobile device 108(see FIG. 1), (2) the websites visited by the user via a browserprovided by mobile device 108 (see FIG. 1), (3) textual information,articles or a summarization of articles displayed on and/or downloadedto mobile device 108 (see FIG. 1) (i.e., textual nugget capture by themobile device 108 (see FIG. 1)), (4) terms entered by the user into asearch engine via mobile device 108 (see FIG. 1), (5) multimedia contentand/or other types of content captured via mobile device 108 (see FIG.1), (6) data specifying characteristic(s) of the environment inproximity to the user as detected and/or measured by sensor(s) coupledto mobile device 108 (see FIG. 1), (7) data specifying function(s) ofthe body of the user or movement(s) of the user as detected and/ormeasured by sensor(s) coupled to mobile device 108 (see FIG. 1), (8) ageographic location of the user provided by a GPS (not shown) coupled tomobile device 108 (see FIG. 1), and (9) other information detected bymobile device 108 or other information the user enters into mobiledevice 108 (see FIG. 1). In another embodiment, the contextualinformation consists of the information listed in (1)-(9) presentedabove.

The contextual information listed in (1)-(9) presented above may belimited by respective time periods. For example, the applications thatthe user has run on mobile device 108 (see FIG. 1) may be theapplications run within the last D1 days, while the summarization ofarticles read by the user on mobile device 108 (see FIG. 1) may be thearticles read within the last D2 days, where D1 can be the same as ordifferent from D2.

In step 206, NLP QA system 104 (see FIG. 1) generates mobile-basedlexicon 114 (see FIG. 1) as a repository or words and other terms, alongwith one or more definitions for each word or other term. The generationof mobile-based lexicon 114 (see FIG. 1) includes NLP QA system 104 (seeFIG. 1) ranking or otherwise prioritizing definitions corresponding toword(s) or term(s) in lexicon 114 (see FIG. 1) based on theaforementioned contextual information determined by mobile device 108(see FIG. 1). In subsequent steps of the process of FIG. 2 or in asubsequent performance of the entire process of FIG. 2, NLP QA system104 (see FIG. 1) can dynamically update the terms in mobile-basedlexicon 114 (see FIG. 1) and the ranking of the terms. In oneembodiment, mobile-based lexicon 114 (see FIG. 1) is ingested into anatural language processing system included in NLP QA system 104 (seeFIG. 1).

Subsequent to step 206, NLP QA system 104 (see FIG. 1) can extendmobile-based lexicon 114 (see FIG. 1) by mobile device acronym symboldefinition, mobile computing terminology, gesture-based and user emotionsummarization, and augmented reality word definitions and word senses.

In step 208, NLP QA system 104 (see FIG. 1) forecasts what thecontextual information about the user of mobile device 108 (see FIG. 1)will be at a specified time in the future. The forecasted contextualinformation is based on historical usage of mobile device 108 (see FIG.1), including any combination of (1) applications that the user has runon mobile device 108 (see FIG. 1), (2) websites visited by the user viaa browser provided by mobile device 108 (see FIG. 1), (3) textualinformation, articles or a summarization of articles displayed on ordownloaded to mobile device 108 (see FIG. 1), (4) terms entered by theuser into a search engine via mobile device 108 (see FIG. 1), and (5)multimedia content and/or other types of content captured via mobiledevice 108 (see FIG. 1). In one embodiment, the forecasted contextualinformation and is based in part on historical usage of mobile device108 (see FIG. 1) and based in part on a combination of: geographicposition(s) at which mobile device 108 was located as determined by aGPS coupled to the mobile device 108 (see FIG. 1), data specifyingcharacteristic(s) of the environment in proximity to the user asdetected and/or measured by sensor(s) coupled to mobile device 108 (seeFIG. 1), and data specifying function(s) of the body of the user ormovement(s) of the user as detected and/or measured by sensor(s) coupledto mobile device 108 (see FIG. 1).

The forecasting performed in step 208 may use any of the forecastingalgorithms shown in FIGS. 4A-4C, or a forecasting algorithm (i.e.,forecaster) that includes mobile-based time series manipulation andpattern recognition, autoregressive integrated moving average (ARIMA)based modeling based on the aforementioned contextual information of theuser as determined by mobile device 108 (see FIG. 1), lag-based modelingbased on the contextual information of the user as determined by mobiledevice 108 (see FIG. 1), residual calculations based on the contextualinformation of the user as determined by mobile device 108 (see FIG. 1),or probability density based functions such as logistic regression basedon mobile-based event detection. In one embodiment, the forecasting instep 208 includes querying the user of mobile device 108 (see FIG. 1),whose response provides additional information to the aforementionedforecasting algorithm so that inferences generated by the forecastingalgorithm about the contextual information are increased, as compared toinferences generated by the forecasting algorithm operating without theadditional information.

In one embodiment, a mobile context dependent analytical pipeline (notshown) annotates the contextual information forecasted in step 208. Theannotated information creates machine learning features based on thetext in natural language question 106 (see FIG. 1), the candidateanswers generated or modified in the process of FIG. 2, and the contextin which each candidate answer appeared, such as passages or evidences.

In one embodiment, a mobile forecaster pipeline (not shown) annotatesthe contextual information forecasted in step 208, thereby creatingmachine learning features based on the text of natural language question106 and the candidate answers generated or modified in the process ofFIG. 2, without regard to the context in which the candidate answerappeared.

In step 210, based in part on the prioritization of definitions ofword(s) and/or other term(s) in mobile-based lexicon 114 (see FIG. 1)generated in step 206 and the contextual information about the userforecasted in step 208, NLP QA system 104 (see FIG. 1) ranks thecandidate answers generated in step 204. The candidate answers rankedfrom the lowest ranked candidate answer to the highest ranked candidateanswer provides candidate answers ordered by how likely each answer is acorrect answer to natural language question 106 (see FIG. 1) (i.e.,ordered from the candidate answer that is least likely to be the correctanswer to natural language question 106 (see FIG. 1) to the candidateanswer that is most likely to be the correct answer to natural languagequestion 106 (see FIG. 1)). After step 210, NLP QA system 104 (seeFIG. 1) initiates a display on mobile device 108 (see FIG. 1) of thehighest ranked candidate answer as the final answer to natural languagequestion 106 (see FIG. 1). The process of FIG. 2 ends at step 212.

In one embodiment, NLP QA system 104 (see FIG. 1) uses the contextualinformation forecasted in step 208 to perform word sense disambiguationand adjust rankings of terms in mobile-based lexicon 112 (see FIG. 1).Prior to step 210, NLP QA system 104 (see FIG. 1) uses the results ofthe disambiguation and adjusted rankings to add to, delete from, ormodify the candidate answers generated in step 204.

In one embodiment, a machine learning ensemble performs the steps ofFIG. 2 and uses the contextual information forecasted in step 208 toalter or adjust machine learning ensemble weights. The machine learningensemble can include, for example, (1) logistic regression phases androutes, (2) dimensions of evidence refinement, (3) probability densityfunctions, classification techniques, and regression techniques, (4)natural language processing systems, and (5) any data retrieval system.

Example

FIG. 3 depicts an example 300 of ranking a candidate answer by stepsincluded in the process of FIG. 2, in accordance with embodiments of thepresent invention. In step 302, near the end of a month, NLP QA system104 (see FIG. 1) receives from mobile device 108 (see FIG. 1) a questionentered by a user of mobile device 108 (see FIG. 1), where the questionincludes the word “terminal.” Step 302 is an example of an actionincluded in step 202 (see FIG. 2).

In step 304, NLP QA system 104 (see FIG. 1) generates multiple candidateanswers to the question received in step 302, including first, secondand third candidate answers (i.e., Answer 1, Answer 2, and Answer 3,respectively, as shown in FIG. 3). The first candidate answer is basedon “terminal” in the question meaning a reception and departure point inan airport. The second candidate answer is based on “terminal” in thequestion meaning a reception and departure point in a train station. Thethird candidate answer is based on “terminal” in the question meaning areception and departure point in a bus station. Although not shown inFIG. 3, the candidate answers may include another answers that are basedon “terminal” meaning (1) a mechanical device by means of which anelectric connection to an apparatus is established, (2) a point at whichcurrent enters or leaves an electrical device, and (3) an electronic orelectromechanical device for entering data into a computer orcommunications system and displaying data received. Step 304 is anexample of an action included in step 204 (see FIG. 2).

In step 306, using coordinates provided by a GPS coupled to mobiledevice 108 (see FIG. 1), NLP QA system 104 (see FIG. 1) determines thecurrent geographic location of mobile device 108 (see FIG. 1) anddetermines that mobile device 108 (see FIG. 1) is currently located neartrain station XYZ. Step 306 is an example of an action taken prior tostep 206 (see FIG. 2).

In step 308, based on the current location of mobile device 108 (seeFIG. 1) determined in step 306, NLP QA system 104 (see FIG. 1) generatesmobile-based lexicon 114 (see FIG. 1) so that the definitions of theword “terminal” are ranked or otherwise prioritized with the definitionindicating “terminal” means a reception and departure point in a trainstation receiving the highest rank or priority. Step 308 is an exampleof an action included in step 206 (see FIG. 2).

In step 310, NLP QA system 104 (see FIG. 1) determines previous usage ofmobile device 108 (see FIG. 1) by which travel tickets were purchased bythe user of mobile device 108 (see FIG. 1), which indicate the user hasestablished a pattern of traveling from either airport ABC or trainstation XYZ near the end of each month for the last n months, where n isa predetermined number of months.

In a step that not shown in FIG. 3, but is prior to step 312, NLP QAsystem 104 (see FIG. 1) determines the current date.

In step 312, based in part on (1) the previous usage of mobile device108 (see FIG. 1) indicating the user's pattern of traveling from eitherairport ABC or train station XYZ near the end of each month, (2) themobile-based lexicon 114 (see FIG. 1), which prioritizes the definitionof “terminal” associated with a train station, and (3) the current datebeing near the end of the current month, NLP QA system 104 (see FIG. 1)forecasts that the user will be boarding a train at train station XYZ.Step 312 is an example of an action included in step 208 (see FIG. 2).

In step 314, based on (1) the definition of “terminal” associated with atrain station being prioritized in step 308 over all other definitionsof “terminal” in mobile-based lexicon 114 (see FIG. 1), and (2) theforecast made in step 312 that the user will be boarding a train attrain station XYZ, NLP QA system 104 (see FIG. 1) ranks Answer 2 higherthan any other candidate answer generated in step 304 because Answer 2is based on “terminal” meaning a reception and departure point in atrain station. Step 314 is an example of an action included in step 210(see FIG. 2).

FIGS. 4A-4C depict forecasting algorithms that are used in the processof FIG. 2, in accordance with embodiments of the present invention. Inone embodiment, step 208 in FIG. 2 includes mobile-based forecaster 112(see FIG. 1) employing a normalized seasonality partitioning algorithm400 in FIG. 4A. Normalized seasonality partitioning algorithm 400includes partitioning a time period f into seasonality components ormultiple curves using both days and a Powell Optimization process.Normalized seasonality partitioning algorithm 400 includes steps of aprocess of time series stratification and normalization intoa(t_(i))_(d) ^(c) aligned curves that are used forecast the contextualinformation about the user of mobile device 108 (see FIG. 1).

In another embodiment, step 208 in FIG. 2 includes mobile-basedforecaster 112 (see FIG. 1) employing a residual forecaster algorithm420 in FIG. 4B. Residual forecaster algorithm 420 includes matchingamplitudes of historical demand events to future events over atwenty-four hour period. The residual curve generated by residualforecaster algorithm 420 is the maximum curve determined by thedifferences between actual hit value and the interpolated value.

In yet another embodiment, step 208 in FIG. 2 includes mobile-basedforecaster 112 (see FIG. 1) employing a Historical Forecaster ensemblethat uses historical information and the current time of day to developa regression line. The Historical Forecaster ensemble is comprised offive forecasters: Partial Forecaster, Adjusted Average Forecaster, PastForecaster, Vector Forecaster and Quadratic Expansion Forecaster.

The Partial Forecaster included in the historical forecaster employs apartial forecaster algorithm 440 in FIG. 4C. Partial forecasteralgorithm 440 includes forecasting several hours into the future only ifthe current time is at night with an average curve plus one standarddeviation. Half of the data is regressed from the past while the otherdata is within the future. If the current time to predict is within aweekend, only the weekend partial forecaster is applied; otherwise, theentire partial forecaster is implemented. The error of the forecaster isD(b)=v or a predefined constant equal across all forecasts.

The Adjusted Average Forecaster is identical to the partial forecasterwith the exception of its error function and it being applied onlyduring the morning times. The error function of the Adjusted AverageForecaster is equation (1) presented below, which accounts for whetherthe current is before or after the curve.

$\begin{matrix}{{E\left( {O\left( t_{i} \right)} \right)} = \left\{ \begin{matrix}{{O\left( t_{i} \right)} > {1\text{:}1}} \\{{O\left( t_{i} \right)} < {1\text{:}0}} \\{O\left( t_{i} \right)}^{2}\end{matrix} \right.} & (1)\end{matrix}$

The Past Forecaster retrieves the previous 24-hour forecast curve. Theerror function for the Past Forecaster is defined as E(O(t_(i)))=0 sincethe forecast retrieves actual past forecasts that have been corrected.

The Vector Forecaster has the error functionE(b)=((t_(current)−t_(start))/(t_(end)−t_(current))).

The Quadratic Expansion Forecaster is uses quadratic curve regressionthat regresses two hours into the past and projects the curve two hoursinto the future. The error function for the Quadratic ExpansionForecaster is E(b)=((t_(current)−t_(start))/(t_(end)−t_(current))).

Computer System

FIG. 5 is a block diagram of a computer that is included in the systemof FIG. 1 and that implements the process of FIG. 2, in accordance withembodiments of the present invention.

Computer 102 is a computer system that generally includes a centralprocessing unit (CPU) 502, a memory 504, an input/output (I/O) interface506, and a bus 508. Further, computer 102 is coupled to I/O devices 510and a computer data storage unit 512. CPU 502 performs computation andcontrol functions of computer 102, including carrying out instructionsincluded in program code 514 to perform a method of ranking candidateanswers to a natural language question, where the instructions arecarried out by CPU 502 via memory 504. CPU 502 may include a singleprocessing unit, or be distributed across one or more processing unitsin one or more locations (e.g., on a client and server). Program code514 includes program code for mobile-based lexicon generator 110 (seeFIG. 1) and mobile-based forecaster 112 (see FIG. 1).

Memory 504 includes a known computer readable storage medium, which isdescribed below. In one embodiment, cache memory elements of memory 504provide temporary storage of at least some program code (e.g., programcode 514) in order to reduce the number of times code must be retrievedfrom bulk storage while instructions of the program code are carriedout. Moreover, similar to CPU 502, memory 504 may reside at a singlephysical location, including one or more types of data storage, or bedistributed across a plurality of physical systems in various forms.Further, memory 504 can include data distributed across, for example, alocal area network (LAN) or a wide area network (WAN).

I/O interface 506 includes any system for exchanging information to orfrom an external source. I/O devices 510 include any known type ofexternal device, including a display device, keyboard, etc. Bus 508provides a communication link between each of the components in computer102, and may include any type of transmission link, includingelectrical, optical, wireless, etc.

I/O interface 506 also allows computer 102 to store information (e.g.,data or program instructions such as program code 514) on and retrievethe information from computer data storage unit 512 or another computerdata storage unit (not shown). Computer data storage unit 512 includes aknown computer-readable storage medium, which is described below. In oneembodiment, computer data storage unit 512 is a non-volatile datastorage device, such as a magnetic disk drive (i.e., hard disk drive) oran optical disc drive (e.g., a CD-ROM drive which receives a CD-ROMdisk).

Memory 504 and/or storage unit 512 may store computer program code 514that includes instructions that are carried out by CPU 502 via memory504 to rank candidate answers to a natural language question. AlthoughFIG. 5 depicts memory 504 as including program code 514, the presentinvention contemplates embodiments in which memory 504 does not includeall of code 514 simultaneously, but instead at one time includes only aportion of code 514.

Further, memory 504 includes an operating system (not shown) and mayinclude other systems not shown in FIG. 5. The operating system may be aLinux®-based operating system that runs on CPU 502 and provides controlof various components within and/or connected to computer 102. Linux isa registered trademark of Linus Torvalds in the United States, othercountries, or both.

Storage unit 512 and/or one or more other computer data storage units(not shown) that are coupled to computer 102 may store the content ofmobile-based lexicon 114 (see FIG. 1).

As will be appreciated by one skilled in the art, in a first embodiment,the present invention may be a system; in a second embodiment, thepresent invention may be a method; and in a third embodiment, thepresent invention may be a computer program product.

Any of the components of an embodiment of the present invention can bedeployed, managed, serviced, etc. by a service provider that offers todeploy or integrate computing infrastructure with respect to rankingcandidate answers to a natural language question. Thus, an embodiment ofthe present invention discloses a process for supporting computerinfrastructure, where the process includes providing at least onesupport service for at least one of integrating, hosting, maintainingand deploying computer-readable code (e.g., program code 514) in acomputer system (e.g., computer 102) including one or more processors(e.g., CPU 502), wherein the processor(s) carry out instructionscontained in the code causing the computer system to rank candidateanswers to a natural language question. Another embodiment discloses aprocess for supporting computer infrastructure, where the processincludes integrating computer-readable program code into a computersystem including a processor. The step of integrating includes storingthe program code in a computer-readable storage device of the computersystem through use of the processor. The program code, upon beingexecuted by the processor, implements a method of ranking candidateanswers to a natural language question.

While it is understood that program code 514 for ranking candidateanswers to a natural language question may be deployed by manuallyloading directly in client, server and proxy computers (not shown) vialoading a computer-readable storage medium (e.g., computer data storageunit 512), program code 514 may also be automatically orsemi-automatically deployed into computer 102 by sending program code514 to a central server or a group of central servers. Program code 514is then downloaded into client computers (e.g., computer 102) that willexecute program code 514. Alternatively, program code 514 is sentdirectly to the client computer via e-mail. Program code 514 is theneither detached to a directory on the client computer or loaded into adirectory on the client computer by a button on the e-mail that executesa program that detaches program code 514 into a directory. Anotheralternative is to send program code 514 directly to a directory on theclient computer hard drive. In a case in which there are proxy servers,the process selects the proxy server code, determines on which computersto place the proxy servers' code, transmits the proxy server code, andthen installs the proxy server code on the proxy computer. Program code514 is transmitted to the proxy server and then it is stored on theproxy server.

Another embodiment of the invention provides a method that performs theprocess steps on a subscription, advertising and/or fee basis. That is,a service provider, such as a Solution Integrator, can offer to create,maintain, support, etc. a process of ranking candidate answers to anatural language question. In this case, the service provider cancreate, maintain, support, etc. a computer infrastructure that performsthe process steps for one or more customers. In return, the serviceprovider can receive payment from the customer(s) under a subscriptionand/or fee agreement, and/or the service provider can receive paymentfrom the sale of advertising content to one or more third parties.

The present invention may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) (memory 504 and computer data storageunit 512) having computer readable program instructions 514 thereon forcausing a processor (e.g., CPU 502) to carry out aspects of the presentinvention.

The computer readable storage medium can be a tangible device that canretain and store instructions (e.g., program code 514) for use by aninstruction execution device. The computer readable storage medium maybe, for example, but is not limited to, an electronic storage device, amagnetic storage device, an optical storage device, an electromagneticstorage device, a semiconductor storage device, or any suitablecombination of the foregoing. A non-exhaustive list of more specificexamples of the computer readable storage medium includes the following:a portable computer diskette, a hard disk, a random access memory (RAM),a read-only memory (ROM), an erasable programmable read-only memory(EPROM or Flash memory), a static random access memory (SRAM), aportable compact disc read-only memory (CD-ROM), a digital versatiledisk (DVD), a memory stick, a floppy disk, a mechanically encoded devicesuch as punch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions (e.g., program code 514)described herein can be downloaded to respective computing/processingdevices (e.g., computer 102) from a computer readable storage medium orto an external computer or external storage device (e.g., computer datastorage unit 512) via a network (not shown), for example, the Internet,a local area network, a wide area network and/or a wireless network. Thenetwork may comprise copper transmission cables, optical transmissionfibers, wireless transmission, routers, firewalls, switches, gatewaycomputers and/or edge servers. A network adapter card (not shown) ornetwork interface (not shown) in each computing/processing devicereceives computer readable program instructions from the network andforwards the computer readable program instructions for storage in acomputer readable storage medium within the respectivecomputing/processing device.

Computer readable program instructions (e.g., program code 514) forcarrying out operations of the present invention may be assemblerinstructions, instruction-set-architecture (ISA) instructions, machineinstructions, machine dependent instructions, microcode, firmwareinstructions, state-setting data, or either source code or object codewritten in any combination of one or more programming languages,including an object oriented programming language such as Smalltalk, C++or the like, and conventional procedural programming languages, such asthe “C” programming language or similar programming languages. Thecomputer readable program instructions may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider). In some embodiments, electronic circuitry including, forexample, programmable logic circuitry, field-programmable gate arrays(FPGA), or programmable logic arrays (PLA) may execute the computerreadable program instructions by utilizing state information of thecomputer readable program instructions to personalize the electroniccircuitry, in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations (e.g., FIG. 2) and/or block diagrams (e.g., FIG.1 and FIG. 5) of methods, apparatus (systems), and computer programproducts according to embodiments of the invention. It will beunderstood that each block of the flowchart illustrations and/or blockdiagrams, and combinations of blocks in the flowchart illustrationsand/or block diagrams, can be implemented by computer readable programinstructions (e.g., program code 514).

These computer readable program instructions may be provided to aprocessor (e.g., CPU 502) of a general purpose computer, special purposecomputer, or other programmable data processing apparatus (e.g.,computer 102) to produce a machine, such that the instructions, whichexecute via the processor of the computer or other programmable dataprocessing apparatus, create means for implementing the functions/actsspecified in the flowchart and/or block diagram block or blocks. Thesecomputer readable program instructions may also be stored in a computerreadable storage medium (e.g., computer data storage unit 512) that candirect a computer, a programmable data processing apparatus, and/orother devices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions (e.g., program code 514) mayalso be loaded onto a computer (e.g. computer 102), other programmabledata processing apparatus, or other device to cause a series ofoperational steps to be performed on the computer, other programmableapparatus or other device to produce a computer implemented process,such that the instructions which execute on the computer, otherprogrammable apparatus, or other device implement the functions/actsspecified in the flowchart and/or block diagram block or blocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

While embodiments of the present invention have been described hereinfor purposes of illustration, many modifications and changes will becomeapparent to those skilled in the art. Accordingly, the appended claimsare intended to encompass all such modifications and changes as fallwithin the true spirit and scope of this invention.

What is claimed is:
 1. A method of ranking candidate answers to anatural language question, the method comprising the steps of: acomputer receiving the natural language question from a mobile devicevia a computer network by which the computer and the mobile device arecoupled, the natural language question being asked by a user of themobile device; the computer generating candidate answers to the receivednatural language question; subsequent to the step of generating thecandidate answers, the computer identifying first contextual informationabout the user, the first contextual information including (1) interestsof the user based on historical usage of the mobile device by the userto run applications on the mobile device, visit websites via a browserprovided by the mobile device, display textual articles on the mobiledevices, enter terms into a search engine via the mobile device, andcapture multimedia content, (2) a geographic location of the userprovided by a global positioning system (GPS) coupled to the mobiledevice, (3) data specifying characteristics of an environment inproximity to the user, the characteristics of the environment beingdetected and measured by a first sensor coupled to the mobile device,and (4) data specifying a bodily function of the user, the bodilyfunction being detected and measured by a second sensor coupled to themobile device; based on the first contextual information, the computerdetermining a prioritization of definitions of terms; based on the firstcontextual information and the prioritization of the definitions of theterms, the computer generating a lexicon of the terms; using aprobability density function and based on (1) the historical usage ofthe mobile device by the user to run the applications on the mobiledevice, visit the websites via the browser provided by the mobiledevice, display the textual articles on the mobile devices, enter theterms into the search engine via the mobile device, and capture themultimedia content, (2) the geographic location of the user provided bythe GPS coupled to the mobile device, (3) the data specifyingcharacteristics of the environment in proximity to the user, and (4) thedata specifying the bodily function of the user, the computerforecasting second contextual information that indicates future behaviorof the user; based on the forecasted second contextual information, thecomputer performing word sense disambiguation of the terms in thelexicon and adjusting the prioritization of the definitions of the termsin the lexicon; based on the word sense disambiguation of the terms inthe lexicon and the adjusted prioritization of the definitions of theterms, the computer modifying the candidate answers; based in part onthe adjusted prioritization of the definitions of the terms in thelexicon, the modified candidate answers, and the forecasted secondcontextual information, the computer ranking the modified candidateanswers to the natural language question, the highest ranked modifiedcandidate answer being more likely to be a correct answer to the naturallanguage question than the other candidate answers.
 2. The method ofclaim 1, further comprising the computer adjusting weights of a machinelearning ensemble based on the forecasted second contextual information,wherein the machine learning ensemble includes (1) logistic regressionphases and routes, (2) dimensions of evidence refinement, (3)probability density functions, classification techniques, and regressiontechniques, (4) natural language processing systems, and (5) a dataretrieval system.
 3. The method of claim 1, wherein the step ofgenerating the lexicon includes generating the lexicon based on textualinformation displayed by the mobile device to the user.
 4. The method ofclaim 1, further comprising providing at least one support service forat least one of creating, integrating, hosting, maintaining, anddeploying computer-readable program code in the computer, the programcode being executed by a processor of the computer to implement thesteps of receiving, generating the candidate answers, identifying thefirst contextual information, determining the prioritization of thedefinitions of the terms, generating the lexicon, forecasting,performing the word sense disambiguation of the terms in the lexicon,modifying the candidate answers, and ranking.
 5. The method of claim 1,wherein the step of forecasting the second contextual informationincludes utilizing a software-based forecaster that employsautoregressive integrated moving average (ARIMA) based modeling.
 6. Themethod of claim 1, wherein the step of forecasting the second contextualinformation includes utilizing a software-based forecaster that employslag-based modeling.
 7. The method of claim 1, wherein the step offorecasting the second contextual information includes utilizing asoftware-based forecaster that employs residual calculations.
 8. Themethod of claim 1, wherein the step of receiving the natural languagequestion includes receiving a question about a treatment for a medicalcondition of the user, the question not including a country in which theuser is located, wherein the step of identifying the first contextualinformation about the user includes identifying the current geographiclocation of the user provided by the GPS coupled to the mobile device,and wherein the step of ranking the modified candidate answers is basedin part on the current geographic location of the user.
 9. The method ofclaim 1, wherein the steps of determining the prioritization of thedefinitions of the terms based on the first contextual information,generating the lexicon of terms based on the first contextualinformation and the prioritization of the definitions, forecasting thesecond contextual information, performing word sense disambiguation,adjusting the prioritization of the definitions, modifying the candidateanswers, and ranking the modified candidate answers are an enhancementto a question answering system that, without the enhancement, deliversanswers to questions by receiving and parsing input text, looking formultiple candidate answers in a data set, and assigning confidencescores to respective candidate answers without taking into account acontext of users who ask the questions.
 10. A computer program product,comprising: a computer-readable storage device; and a computer-readableprogram code stored in the computer-readable storage device, thecomputer-readable program code containing instructions that are carriedout by a central processing unit (CPU) of a computer system to implementa method of ranking candidate answers to a natural language question,the method comprising the steps of: the computer system receiving thenatural language question from a mobile device via a computer network bywhich the computer system and the mobile device are coupled, the naturallanguage question being asked by a user of the mobile device; thecomputer system generating candidate answers to the received naturallanguage question; subsequent to the step of generating the candidateanswers, the computer system identifying first contextual informationabout the user, the first contextual information including (1) interestsof the user based on historical usage of the mobile device by the userto run applications on the mobile device, visit websites via a browserprovided by the mobile device, display textual articles on the mobiledevices, enter terms into a search engine via the mobile device, andcapture multimedia content, (2) a geographic location of the userprovided by a global positioning system (GPS) coupled to the mobiledevice, (3) data specifying characteristics of an environment inproximity to the user, the characteristics of the environment beingdetected and measured by a first sensor coupled to the mobile device,and (4) data specifying a bodily function of the user, the bodilyfunction being detected and measured by a second sensor coupled to themobile device; based on the first contextual information, the computersystem determining a prioritization of definitions of terms; based onthe first contextual information and the prioritization of thedefinitions of the terms, the computer system generating a lexicon ofthe terms; using a probability density function and based on (1) thehistorical usage of the mobile device by the user to run theapplications on the mobile device, visit the websites via the browserprovided by the mobile device, display the textual articles on themobile devices, enter the terms into the search engine via the mobiledevice, and capture the multimedia content, (2) the geographic locationof the user provided by the GPS coupled to the mobile device, (3) thedata specifying characteristics of the environment in proximity to theuser, and (4) the data specifying the bodily function of the user, thecomputer system forecasting second contextual information that indicatesfuture behavior of the user; based on the forecasted second contextualinformation, the computer system performing word sense disambiguation ofthe terms in the lexicon and adjusting the prioritization of thedefinitions of the terms in the lexicon; based on the word sensedisambiguation of the terms in the lexicon and the adjustedprioritization of the definitions of the terms, the computer systemmodifying the candidate answers; based in part on the adjustedprioritization of the definitions of the terms in the lexicon, themodified candidate answers, and the forecasted second contextualinformation, the computer system ranking the modified candidate answersto the natural language question, the highest ranked modified candidateanswer being more likely to be a correct answer to the natural languagequestion than the other candidate answers.
 11. The program product ofclaim 10, wherein the method further comprises the computer systemadjusting weights of a machine learning ensemble based on the forecastedsecond contextual information, wherein the machine learning ensembleincludes (1) logistic regression phases and routes, (2) dimensions ofevidence refinement, (3) probability density functions, classificationtechniques, and regression techniques, (4) natural language processingsystems, and (5) a data retrieval system.
 12. The program product ofclaim 10, wherein the step of generating the lexicon includes generatingthe lexicon based on textual information displayed by the mobile deviceto the user.
 13. The computer program product of claim 10, wherein thestep of forecasting the second contextual information includes utilizinga software-based forecaster that employs autoregressive integratedmoving average (ARIMA) based modeling.
 14. The computer program productof claim 10, wherein the step of forecasting the second contextualinformation includes utilizing a software-based forecaster that employslag-based modeling.
 15. The computer program product of claim 10,wherein the step of forecasting the second contextual informationincludes utilizing a software-based forecaster that employs residualcalculations.
 16. The computer program product of claim 10, wherein thestep of receiving the natural language question includes receiving aquestion about a treatment for a medical condition of the user, thequestion not including a country in which the user is located, whereinthe step of identifying the first contextual information about the userincludes identifying the current geographic location of the userprovided by the GPS coupled to the mobile device, and wherein the stepof ranking the modified candidate answers is based in part on thecurrent geographic location of the user.
 17. The computer programproduct of claim 10, wherein the steps of determining the prioritizationof the definitions of the terms based on the first contextualinformation, generating the lexicon of terms based on the firstcontextual information and the prioritization of the definitions,forecasting the second contextual information, performing word sensedisambiguation, adjusting the prioritization of the definitions,modifying the candidate answers, and ranking the modified candidateanswers are an enhancement to a question answering system that, withoutthe enhancement, delivers answers to questions by receiving and parsinginput text, looking for multiple candidate answers in a data set, andassigning confidence scores to respective candidate answers withouttaking into account a context of users who ask the questions.
 18. Acomputer system comprising: a central processing unit (CPU); a memorycoupled to the CPU; and a computer readable storage device coupled tothe CPU, the storage device containing instructions that are executed bythe CPU via the memory to implement a method of ranking candidateanswers to a natural language question, the method comprising the stepsof: the computer system receiving the natural language question from amobile device via a computer network by which the computer system andthe mobile device are coupled, the natural language question being askedby a user of the mobile device; the computer system generating candidateanswers to the received natural language question; subsequent to thestep of generating the candidate answers, the computer systemidentifying first contextual information about the user, the firstcontextual information including (1) interests of the user based onhistorical usage of the mobile device by the user to run applications onthe mobile device, visit websites via a browser provided by the mobiledevice, display textual articles on the mobile devices, enter terms intoa search engine via the mobile device, and capture multimedia content,(2) a geographic location of the user provided by a global positioningsystem (GPS) coupled to the mobile device, (3) data specifyingcharacteristics of an environment in proximity to the user, thecharacteristics of the environment being detected and measured by afirst sensor coupled to the mobile device, and (4) data specifying abodily function of the user, the bodily function being detected andmeasured by a second sensor coupled to the mobile device; based on thefirst contextual information, the computer system determining aprioritization of definitions of terms; based on the first contextualinformation and the prioritization of the definitions of the terms, thecomputer system generating a lexicon of the terms; using a probabilitydensity function and based on (1) the historical usage of the mobiledevice by the user to run the applications on the mobile device, visitthe websites via the browser provided by the mobile device, display thetextual articles on the mobile devices, enter the terms into the searchengine via the mobile device, and capture the multimedia content, (2)the geographic location of the user provided by the GPS coupled to themobile device, (3) the data specifying characteristics of theenvironment in proximity to the user, and (4) the data specifying thebodily function of the user, the computer system forecasting secondcontextual information that indicates future behavior of the user; basedon the forecasted second contextual information, the computer systemperforming word sense disambiguation of the terms in the lexicon andadjusting the prioritization of the definitions of the terms in thelexicon; based on the word sense disambiguation of the terms in thelexicon and the adjusted prioritization of the definitions of the terms,the computer system modifying the candidate answers; based in part onthe adjusted prioritization of the definitions of the terms in thelexicon, the modified candidate answers, and the forecasted secondcontextual information, the computer system ranking the modifiedcandidate answers to the natural language question, the highest rankedmodified candidate answer being more likely to be a correct answer tothe natural language question than the other candidate answers.
 19. Thecomputer system of claim 18, wherein the method further comprises thecomputer system adjusting weights of a machine learning ensemble basedon the forecasted second contextual information, wherein the machinelearning ensemble includes (1) logistic regression phases and routes,(2) dimensions of evidence refinement, (3) probability densityfunctions, classification techniques, and regression techniques, (4)natural language processing systems, and (5) a data retrieval system.20. The computer system of claim 18, wherein the step of generating thelexicon includes generating the lexicon based on textual informationdisplayed by the mobile device to the user.